Capillary tube gas discharge display panels and devices

ABSTRACT

There is disclosed a multiple discharge gas display/memory panel of the type in which filamentary or capillary size gas tubes or gas continuums are assembled and formed as a monolayer to form the gas discharge panel.

I United States Patent 1111 3,602,754

[72] Inventors Lawrence V-Phender [50] Field ofSeai-cli 315/160, Toledo;167, 169; 313/108, 108 B, 108 c, 109.5, 104, 201, Wolfgang W. Bode,Sylvania; Glenn H. 220; 340/166; 350/96 Dunlap, Maumee; Anthony M.Kobylak, Rossford; Raymond s. Richards, Toledo, all 1 References Citedo1, Ohio UNITED STATES PATENTS [21] pp 819,641 2,933,648 4/1960 Bentley315/169 [22] Filed p -2 3,265,892 8/1966 Sheldon..... 350/96X PatentedAug-31,1971 3,505,046 4/1970 Phaneuf 350/96x [73] AssigneeOwens-lllinob, Inc.

[54] CAPILLARY TUBE GAS DISCHARGE DISPLAY Primary Examiner-Roy LakeAssistant Examiner-E. R. La Roche A1torneysE. J. Holler and D. K.Wedding ABSTRACT: There is disclosed a multiple discharge gasdisplax/memory panel of the type in which filamentary or capillary sizegas tubes or gas continuums are assembled and formed as a monolayer toform the gas discharge panel.

PANELS AND DEVICES 1 1 Claims, 29 Drawing Figs.

52 us. c1. 313/108 B, 313/201, 313/220, 315/169 R, 340/166 R 51 1m. 01..H0lj 11/02, i 1101 65/04 PATENTED AUG31 1271 SHEET 2 0F 4 CAPILLARYTUBE GAS DISCHARGE DISPLAY PANELS AND DEVICES The present inventionrelates in general to methods of precision fabrication of complex glassstructures, particularly gas discharge devices and more particularlyrelates to redraw processes for fabricating capillary gas dischargedevices and complex glass structures produced thereby.

Glass redraw processes per se are well known in the art and have beenused to form precision glass tubing, sheets and fiber bundles withcomplex cross sections, such as shown in an article by R. A. Humphrey,entitled Forming Glass Filaments with Unusual Cross Sections, publishedby Gordon & Breach, New York, New York, proceedings of the 7thIntemational Congress on Glass, Brussels, June 28 to July 3, 1965,Charkroi, Belgium pages 77-l to 77-8. The present invention adapts theknown redraw technique in a unique way to produce complex glass panelstructures having high precision dimensions. For example, monolayercombinations of conventional glass structures such as tubes (round,rectangular, etc.), solid rods and plates (grooved, bored, etc.) andcertain conductor arrays are formed in various complex panel units,subunits, etc. An important aspect of the process is that relativelylarge glass structures having complex cross-sectional configurations,corresponding to the complex cross-sectional configurations in the finalproduct or panel device may be easily formed to desired dimensions.During the redrawing or stretching process all cross-sectionaldimensions and areas can be uniformly reduced while the percenttolerance remains constant. Thus, for purposes of illustration, a l-inchdimension having a tolerance of 1 percent e.g., 10.01 inch, in a 10 to 1reduction results in a 0.1 inch dimension and a tolerance of 10.001inch. A further 10 to 1 reduction results in a 0.01 inch dimension and atolerance of 10.0001 inch.

Tubular gas discharge chambers or continuums have been disclosed orotherwise suggested in the prior art, and while in some cases, suchtubular gas discharge chambers have some similarity to structuresdisclosed herein, none has been capillary in the sense of the presentinvention in having precision internal diameter or discharge gaps ofless than about 0.010 inch and larger in some cases with precision ofthin glass walls of about 0.001 inch in thickness, such precision beinga requisite for gas discharge devices having a memory characteristicobtained through storage of charges on wall surfaces. Hence, such priorart disclosures as U.S. Pat. No. 3,050,654 to Toulon and U.S. Pat. No.1,867,340 to Weinhart et al. for example (there being many others),while disclosing gas discharge panels formed of an assembly or array ofgas filled tubes having external electrodes or conductors, such devicesare neither constructed nor operated in the manner of the presentinvention in that such gas filled tube structures as are disclosed inthe prior art have dimensions, operating frequencies and/or potentialsapplied thereto which are inconsistent with the structure and/oroperating conditions of the gas discharge devices described herein.

Basic functional operating features and principles of the presentinvention are disclosed in U.S. Pat. No. 3,499,167 to Baker et al., inwhich a thin gas continuum or other chamber bounded by a thin dielectriccoating on conductor arrays carried on relatively thick substrates orplate members, support a plurality of discrete, side-by-side gasdischarges without any physical discharge is isolation members orstructure in the thin gas chamber, such discharge isolation beingeffected, in part, due to the gas being at a pressure of sufficientmagnitude to confine charges produced on discharge to within anelemental two dimensionally unconfined gas volume within which thedischarges take place. Earlier disclosures of others disclosed generallysimilar pulsing discharges in so-called mini cells" wherein a perforatedthin glass sheet is used to provide physical confinement or isolationfor discrete elemental gas discharges, and there has been suggestion ofmultiple pulsing discharges" in a gas continuum.

Where large numbers of elemental gas discharge volumes are to bemanipulated by common conductor systems, variations in discharge gapand/or dielectric can be sufficient to require different operating ordischarge voltages for manipulating discharges. When such dimensionalvariations exceed design tolerances, some elemental discharge volumesare not properly manipulated. Moreover, effective operating voltages maylikewise vary due to variation in dielectric thickness between theexternal conductors and the dielectric surfacegas medium interface.Significant advances have been made by the assignee of the presentinvention in providing solutions to these problems in the way ofimprovement materials, fabricating techniques, and gas compositions andpressures. The present invention, while incorporating the highlydesirable feature of the Baker et al. patent in the elimination of thephysical isolation structure such as a perforated center sandwich,provides an alternate structural approach or configuration inachievement of this feature.

In addition to the objective of providing a gas discharge display andmemory device not having any perforated center sandwich or physicalconfinement of discrete elemental discharges as is achieved by theinvention disclosed in the aforementioned Baker et a1. application, thepresent invention has the additional objectives of providing methods offabricating complex glass panel structures with a high degree ofprecision and at relatively low cost; the achievement of simpler,precision manufacture of gas discharge chambers and dielectricboundaries of same; the elimination of possible structural stresses dueto fluctuation in ambient pressure differentials where high gaspressures are desired; the provision of novel methods of precisionmanufacturing display panels in large volumes and at relatively lowcost; the provision of display units which may be very long compared totheir width or vertical height so that a large number of alphanumericcharacters may be written" or displayed in a line, for example, fullsentences, and the provision of various novel tube-rod conductorconfigurations. 1

The above as well as other objects, advantages and features of theinvention will become apparent from the following specification andaccompanying drawings wherein:

FIG. 1 is a partial perspective view of a gas discharge deviceconstructed in accordance with the invention, and

FIG. 2 is a portion of the structure shown in FIG. 1 with exemplarydimensions thereon;

FIG. 3A to FIG. 3D (essentially full scale) show the size reductionsequence to produce the device disclosed in FIGS. I and 2, FIG. 1 beinga greatly enlarged view of the device shown in FIG. 3D (Because of thesmall size, the individual gas passages or continuums thereof do notappear in FIG. 3D.);

FIG. 4 discloses the selected elements of a conventional redrawapparatus which may be used to practice the process disclosed herein,FIG. SA-FIG. 4F, inclusive, illustrating the fabrication sequence forone specific complex glass structure constructed according to theinvention;

FIGS. 5, 6A and B-IOA and B, inclusive, illustrate various noveltube-rod-plate-conductor units or subunits, greatly enlarged,constructed according to the invention; and

FIGS. 11A and B-I2A and B and FIG. 13, inclusive, illustrate complexgrooved-bored-conductor plate structures constructed according to theinvention.

With reference to FIG. 1, capillary tubes 10, rectangularly shaped incross section, are arrayed in parallel side-by-side arrangement with thebores 11 of each capillary tube 10 being in a common plane. Each tubemay be individually sealed or a gas manifold (not shown) may be used atthe end of the tubes to permit gas pressure equalization. Each bore 11is shown as being square having dimensions of 0.005 inch (5 mil) and onthe lower external surface or side of each capillary tube 10 isconductor 12, each conductor 12 being aligned with bore 11 of itsassociated capillary tube 10. On the external surfaces of capillaries 10are conductors 13 which are orthogonally related to conductors 12 todefine a plurality of cross points or discharge units with the gas incapillary tubes 10. The

discharge gaps. namely the distance between gas-glass interface 15 andgas-glass interface 16, are 0.005 inch (5 mil). The thickness of glassbetween conductor 13 in the gas-glass interface is 0.005 inch (5 mil) aswell as the thickness of the dielectric between conductor 12 andgas-dielectric interface 16. It will, of course, be appreciated, thatthe dimensions may be varied by selecting larger or smaller dimensionsfor the initial forms. It is desirable to make the thickness of glassand discharge gap as small as possible. With respect to electricaloperating parameters, these are the critical dimensions which thepresent invention achieves with such precision that the dischargepotentials applied to conductor 12 and any one of conductors 13 will beessentially uniform in the sense of not being affected by departures indielectric thickness and/or discharge gaps defined by the spacingbetween the two gasdielectric interfaces 15 and 16. The thickness ofdielectric or glass capillary tubing walls 18 as well as thegas-dielectric interface l9 and wall are noncritical electrically and inthe embodiment disclosed are approximately 10 mils (0.010 inch) so thatthe spacing between bores 11 of capillary tubing 10 is approximately 20mils (0.020 inch) which, is essence, defines the spacing between line ofdischarge units. More or less spacing may be incorporated as desired.The bores 11 are filled with a gas, such as a mixture of neon andnitrogen as disclosed in the aforesaid Baker et al. Patent or a mixtureof neon and argon as disclosed in application Ser. No. 764,577 to Nolan,filed Oct. 2, I968. The ends of the capillary tubes 10 may be sealed bya hot wire, for example.

Conductors 12 may be printed or otherwise applied on the externalcapillary surfaces, or may be Wires secured to these surfaces.Alternatively, conductors l2 and 13 may be on separate plates (notshown) which are brought into intimate contact with exterior surfaces ofcapillary tubes 10, the only element of positioning precision requiredbeing with respect to the longitudinal orientation of conductors 12 withbores 11 of capillary tubes 10.

FIGS. 3A, 3B, and 3C, with exemplary dimensions shown thereon, show theprecision with which the capillary and other structures of the presentinvention may be fabricated in a redraw process. For example, in orderto construct the glass structures illustrated in FIG. 1, 16 cast glassbillets 10B (shown in approximately full scale in FIG. 3A) areillustrated in a ground and polished starting condition in which thethickness of each billet is lhinches plus or minus 0.030 inch in width;the thickness of the glass walls between gas-glass interfaces 15B and16B and exterior surfaces of the billet being one-half inch plus orminus 0.03 inch. In the event the billets are not ground and polished,the tolerances set forth above may be plus or minus 0.050 inch and thispercentage or proportion of deviation will appear in the finishedproduct. If wider spacing between capillary gas passages or bores 11 isdesired, solid spacer rods may be interposed between billets havingbores therein and reduced in the process. Sixteen such cast billets arearranged in a row approximately 40 inches in width, it being apparentthat the length thereof, except for providing for redraw apparatusconnection to the ends (which are discarded) thereof for the redrawprocess described later herein, is noncritical. As a general guide, for10 to 1 reduction ratios, a 3-foot length of starting assembly willproduce about 300 feet of panel blanks. The billets 10B arrayed as shownin FIG. 3A may be placed in an oven and heated to fuse the contiguousside edges of each billet to each other although this is not essential.The 16 cast billets 10B are placed in the redraw apparatus describedlater herein and redrawn to reduce the crosssectional area of alldimensions equally in proportionate amounts and it will be noted thatthe tolerances are likewise reduced in precisely the same proportions sothat by starting with high precision large numbers, the same accuracy orprecision will appear in the final product. For example, the firstredraw operation uniformly reduces all cross-sectional dimensions at aratio of 10 to 1 so that the overall thickness of the billet is now0.150 inch plus or minus 0.003 inch (a 10 to 1 reduction in thetolerance). The glass-gas interface dimension is likewise reduced from0.50 inch plus or minus 0.03 inch to 0.050 inch plus or minus 0.003inch, a similar reduction in scale. It will also be noted that the widthof the 16 billets has been reduced from 40 inches to 4 inches. (Althoughnot shown, square corners and other sharp angular edges are slightlyrounded filets). FIG. 3D illustrates the final reduction to the desireddimension. In this instance, 10 of the assemblies shown in FIG. 3B areassembled in parallel side-by-side relationship for a second redrawoperation. It will be appreciated that the product of the first drawingshown in FIG. 38 may be redrawn independently or any redraw of aplurality of such units. Furthermore, the individual billets may beredrawn, as

described more fully hereinafter, all individually. It will beunderstood that more or less redrawing operations may be effectedaccording to the desired dimension required in the final product.However, in the complex glass-metal structure disclosed hereinmetal-glass seal or bonding tends to limit the process to one redrawoperation. -It will be noted at this point that the original 16 castbillets 108 shown in FIG. 3A when reduced to the dimension shown in FIG.3B and then reassembled with 10 such assemblies in an array as shown inFIG. 3C have longitudinal semicapillary gas passages or bores '16B-1 sothat in the final product illustrated in FIG. 3D, in which the 40-inchassembly shown in FIG. 3C has been reduced to a 10 to 1 ratio to a 4inch width, there will be 40 capillary gas passages or bores 11 perinch. With reference now to FIG. 3D (which corresponds to FIG. 1), theredrawing of the assembly shown in FIG. 3C results in an overallthickness of 0.015 inch plus or minus 0.0003 inch. The thickness of theglass between gas-dielectric interface 15 to the outer surface ofcapillary tube 10 is 0.005 inch plus or minus 0.0003 inch and thedimensions of the bores 11 are 0.015 inch plus or minus 0.0003 inch.This uniformity and precision of the critical dielectric and gasdischarge gap dimensions in the resulting product is achieved byessentially starting with large structures which may be closelycontrolled as to critical dimensions in the final product. Large numbersof display panel blanks may be assembled for larger display areas andare relatively immune from stress due to ambient pressure differentials.

The same degree of dimensional precision and manufacturing economy iseffected in more complex panel structures disclosed herein, and will bedescribed in connection with FIG. 4F in which hollow tubes, solid rodsand a solid backup plate constitute the starting structures.

With respect to FIG. 4F the glass used for the rods and tubes may beKG-33 rod and tubes which is available from the assignee of the presentinvention. The backup plate may be chemically and heat resistant,laboratory glassware (as for example a composition containing 80.5percent Si0 12.9 percent B 0 3.8 percent Na,0, 0.4 percent K 0 and 2.2percent AMO which is available in sheet form of any desired thickness.To take most advantage of the redraw process in reducing tube, rod andbackup plate including normal manufacturing tolerances, a large tube androd diameter l-inch outside diameter) was selected as being of optimumsize. The process sequence in the final redraw product of FIG. 4F was asfollows:

1. Redraw the l-inch outside diameter rod to 0060/0065, a

16 to 1 reduction.

2. Redraw the l-inch outside diameter tubing to 0080/0085, a I2 to 1reduction.

3. Lay up 15 redrawn tubes (1) and 58 redrawn rods (2) on a 7%-inch widesheet backup plate and oven fuse same.

4. Redraw the fused assembly to the desired width (approximately a 10 to1 reduction).

This fabrication sequence is in part illustrated in FIGS. 4A to 4F withthe size and theoretical tolerances shown at the various steps. Thepurpose of fusing the rods and tubes to the backup plate is to avoidslumping during the redraw process. Fusing temperature of about l300 F.was found to be satisfactory with good fusion on all rods and tubes withno apparent slumping or deformation. This assembly was inserted in theapparatus shown in FIG. 4 and redrawn to the desired dimensions.

DESCRIPTION OF REDRAW APPARATUS AND METHOD Figure 4 illustrates one formof essentially conventional redraw apparatus used in fabricatingcapillary gas discharge panels disclosed herein. This apparatus asillustrated is conventional and forms no part of the present invention.While FIG. 4 will be described in connection with redrawing thecapillary tube-rod-backup plate assembly illustrated in FIG. 4F, it willbe appreciated that except for minor modification to accommodate thedifferent tube and/or rod configurations, the apparatus may be useful inredrawing all forms of discharge devices disclosed herein. As shown, theredraw apparatus includes a feed mechanism 150, preheat infrared lamps151, multizone controllable furnace 152, and drawing mechanism 153. Feedmechanism assembly 150 includes a direct current motor 160 which issupplied from a conventional variable direct current supply (not shown)to vary the speed of motor 160. A pulley 161 on motor 160 is coupled bya drive belt 162 to pulley 163 on speed reducer gear assembly 164. Theoutput of speed reducer mechanism 164 is taken from a pulley 166 whichis coupled by belt 167 to wheel 168 which has a pair of threaded splitnuts 169A and 169B to be rotated with wheel 168. A threaded rod 170 ismeshed with teeth (not shown) in split nuts 169A and 169B so that whenpulley 168 is rotated in the direction of the arrow, rod 170 movesupwardly at a controlled rate of speed. Clamp assembly 171 fixed to theupper end of rod 170 is thus moved upwardly at a controllable rate ofspeed. Clamp assembly 171 clamps the lowermost end of tube-rod-backupplate assembly S and feeds same upwardly in the direction of arrowillustrated. The upper end of the assembly 8, after being heated toredraw temperature, is grabbed by a tong or clamp (not shown) and pulledupwardly beyond draw rolls 180-181, which are spread apart for thispurpose to permit passage of the clamp.

Prior to entering the multistage or zone electric furnace 152, theassembly S is preheated by a bank of infrared lamps 151. Furnace 152 isconventional, and as shown consists of two separate heating stages 152Aand 1523 which are supplied from electrical alternating current supply(not shown) which may be adjustable to adjust the temperature in thefurnace, and it will be apparent that the stages may be individuallycontrolled so that the heat directed to the assembly S from front orback may be adjusted in any desired fashion. Suffice to say, multistagefurnace 152 heats tube-rod-backup plate assembly S to a redrawtemperature. In the example being described, this temperature is betweenthe annealing point (KG-33 tube and rod and backup plate 565 C.) and thefiber softening point (KG-33 tube and rod 825 C., backup plate 820 C.),and was measured by a thermocouple spaced about one-half inch from theglass assembly S at zone R. The redraw assembly S is pulled upwardly ata selected rate of speed by a pair of counterrotating draw rolls 180 and181 by gear assembly 182. Redraw roll 181 is driven from the outputshaft 183 of speed reducer assembly or mechanism 184 which in turn isdriven by a pulley 186 belted to the drive pulley 187 on a secondvariable speed direct current motor 188. The variable speed motor 188 issupplied from direct current from a supply (not shown) and its speed maybe adjusted for different draw rates and/or conditions as desired.Likewise, motor 160 may be adjusted in speed for different draw ratesand/or draw conditions as desired. These speeds and the temperature ofmultistage of 152 may all be adjusted by conventional control apparatusin accordance with known redraw techniques and form no part of thepresent invention.

While the apparatus shown in Figure is known in the art as an up-draw"assembly, it will be appreciated that with due consideration for theeffect of gravity on the softened glass the order may be reversed inthat the feed mechanism 150 may be in the position of the redrawmechanism 153 so as to down draw the glass. Moreover, the redraw processmay be applied horizontally or angularly. FIG. 45 illustrates theassembly S prior to redraw with exemplary dimensions given; 10 to lreductions in dimensions are preferred with a product yield of aboutfeet for each foot of starting assembly. After passing draw rolls 180,181, the assembly is scored and severed to any desired length.

The current supplied to furnace 152 may be controlled by conventionalthermocouples (not shown) or other temperature sensing devices (suitablylocated) and used to produce signals for controlling current to furnaceheaters or otherwise controlling temperatures of the furnaces in aconventional manner. Obviously, other conventional for-ms of furnacesand temperature controls may be used.

In FIG. 4, zone R denotes the transition for a solid state to a plasticstate and back to a solid state so that application of Iongitudinaltension will stretch or draw the tube-rod-backup plate assembly Suniformly and reduce the cross-sectional dimensions of all components ofassembly S. All other adjustable parameters remaining fixed, thereduction rate may be set by the speed of draw rolls 180 and 181 andrate of feed of assembly S by feed screw rod 170. It can be seen thatthe differential of velocity between draw rolls 180 and 181 and feedscrew rod results in the application of the aforesaid longitudinaltension or drawing force to assembly S. Other apparatus may be used forapplying drawing force or longitudinal tension to assembly S. In a lesspreferred way, the differential velocity may be maintained constant andthe viscosity of the softened glass adjusted by increase of temperatureto vary the draw rate.

Referring now to FIGS. 4A, 4B, 4C, 4D, 4E, and 4F, the specific processfor assembling the tube-rod-backup assembly S of FIG. 10 will bedescribed. As shown in FIG. 4A, glass tubing having a l-inch outsidediameter plus or minus 0.034 inch and wall thickness of 5/32 inch plusor minus 0.017 inch, in an initial or starting condition, is reduced orredrawn to a tube having an outside diameter between 0.080 inch to 0.085inch and a wall thickness between 0.0144 inch and 0.0116 inch (a 12 to 1reduction) as exemplified in the redraw tubing 41 shown in FIG. 48.Similarly, rod 42 of FIG. 4A having a linch outside diameter is reducedto a dimension of 0.060 and 0.065 inch (a 16 to 1 reduction) and theredrawn rod 43 is shown in FIG. 4B. It will be appreciated that greateror lesser reductions may be effected according to specific dimensionsdesired. Redraw tubes 41 and redraw rod 43 are assembled on plate 44having a length corresponding to the length of the tubes and rods.Spacers 46 may be mounted at the corners or the edges of the plate 44although this is not necessary. Preferably, prior to redraw, thetube-rod-plate assembly is placed in a fusing oven and heated to atemperature of about 1300 F. to fuse the contacting surfaces oftube-rod-plate assembly to each other to avoid slumping during theredraw process. A cross-sectional view of the tube-rod-backup plateassembly 8 prior to redraw is shown in FIG. 4E (exemplary dimensionsbeing shown). This assembly comprises 15 redrawn tubes 41, 58 redrawrods 43, there being four rods 43 interposed between each tube 41 in theassembly with one additional rod 43A at each side of the terminal tubes41T of the assembly. Rods 43 simply serve as spacers and may beeliminated if desired. After the reducing operation, performed by theapparatus shown in FIG. 4, the assembly S is as appears in FIG. 4E,having been a 10 to 1 reduction in overall cross-sectional dimensionsand a lengthening of the entire product or assembly. Thus, withreference to FIG. 4E, the 7%-inch wide backup plate has been reduced inwidth to 0.75 inch. The thickness of the backup plate 44 has beenreduced from 0.06 inch to 0.006 inch. The width of the tube-rod-backupplate assembly has likewise been proportionately reduced from 5.063inches (4.6785) to 0.5063 inch (0.4687). Furthermore, there has been acorresponding reduction in the center-to-center spacing of tubes 41.Thus, the 03462 (0.3204) center-to-center spacing of tubes 41 has beenreduced proportionately to 0.03462 inch (0.03205) which amounts to aspacing per line of about 30 capillary discharge tubes per inch.Similarly, the cross-sectional dimension of each tube 41 as beenproportionately reduced from the initial outside diameter of 0.080 inch(0.085) to 0.0080 inch (0.0085 inch) and the wall thicknesses of tubing41 have been correspondingly reduced from 0.0144 inch (0.01 16 inch) to0.00144 inch (0.001 16 inch).

From the foregoing specific examples, it can be seen that the redrawtechnique reduces the cross-sectional dimensions of tubing-rods-plates,etc., proportionate amounts whereas tolerances are reduced in the samedirection so that precision tubing and dimensions are obtained.Obviously, more precise starting dimensions result in products havingvery high precision.

FIGS. 6A-10-B, inclusive, illustrate various other tube-rodbackup plateassemblies and configurations fabricated in accordance with technique ofthe present invention. Thus, FIG. 6A illustrates structurescorresponding to FIG. 1 in which the capillary tubes are rectangular,the light emitting unit consists of a single bore 1 1 of a tube with thebore being the same size as the conductors C so that the unit excites ordischarges within one bore. A departure from the unit illustrated inFIG. 6A is shown in FIG. 6B in which the applied conductors C are largerin width than the bore 11' of a capillary tube so that discrete gasvolumes in several capillary tubes spanned by the width of the conductorC are excited or discharged. In other words, the discharge" takes placewithin several contiguous bores of capillary tubing.

FIG. 7A illustrates the invention as applied to essentially round tubesand, like the embodiment illustrated in FIG. 6A, the bore of thecapillary tube T is approximately the same size as or larger than thewidth of the conductors C applied thereto so that the discharge takesplace within one capillary bore. FIG. 7B is similar to FIG. 6B in thatthe conductors C have a width spanning more than one capillary bore sothat the discharge takes place within several capillary bores contiguousto one another.

In FIG. 8A, essentially round tubes are disclosed and tangential to eachcapillary tube is a solid rod of glass fiber R and the conductor Cwidth, running longitudinal to the longitudinal length of the capillarytube, spans only one capillary tube so that the discharge takes placewithin one bore. In FIG. 8B, the spacer rods or solid fibers R haveessentially the same diameter as the outside diameter of a capillarytube. In the above described round tube embodiments, instead of usingprinted conductors paralleling the longitudinal axes of the bores, smallgauge wires W (about 1-1 mils) may be laid in the groove or notch Nbetween a round tube and contiguous rod as shown at the right side ofFIG. 8B. In this modification, the conductor wire W is off set so as tonot block light emission from a discrete discharge to a viewer V.

In FIG. 9A, essentially round capillary tubes T are sandwiched between apair of cover plates P. The structure illustrated without conductors Cmay be assembled with large tubes sandwiched between large cover platesand redrawn to desired dimensions as a single unit, after whichconductors C may be applied to the exterior surfaces of the cover plateP. FIG. 9B shows a similar structure additionally having spacer rods Rinterposed between tubes T. Conductors C may span several tube bores formultiple discharges or single bores for single discharges. It will beappreciated that the tubes need not be contiguous or separated by solidspacer rods so as to leave open spaces between tubes.

In FIG. 10A and FIG. 10B, there are no capillary bores as such. Thesestructures consist essentially of solid fiber rods R sandwiched betweencover plates P, all of which have been redrawn as a unit. In theseembodiments the discharge gas is located in the interstices 1 betweenrods R and the discharge is at the interstices I.

FIGS. llA-13 illustrate the invention as applied to other complexcross-sectional configurations particularly adapted for gas dischargepanels in which essentially rectangularly spaced glass sheets havingnonglass geometrical shapes therein are redrawn to produce thestructures illustrated. In

FIG. 11A, the two halves 200 and 201 are identical. Each half isinitially formed from a glass plate 202 having parallel grooves 203 sawnor otherwise formed therein, said grooves being essentially rectangularnonglass areas. Aligned with grooves 203 are conductors 204. Conductors204 are attenuated in cross-sectional area simultaneously in the sameproportion as the attenuation of the cross-sectional area of grooves203. Such conductors may be indium metal or other conductive alloy orother suitable conductors which are liquid at glass drawing temperatureof glass plate 202 and are placed in bores paralleling grooves 203 priorto redraw of the plate.

In the embodiment of FIG. 11A, the depth of grooves 203 are madeone-half the discharge gap distance so that when the two halves 200 and201 are assembled the discharge gap will equal groove intersectionsbetween plates 200 and 201. In FIG. 118 only one plate is grooved orchanneled, the depth of the grooves 203 being equal to the discharge gapdistance. Conductors 204' are formed in the manner described above.Complex glass-metal-capillary gas channel structures according to theinvention need not necessarily involve multiple conductors and gaschannels. For example, as shown in Figure 5, a single conductor 210 anda single parallel gas capillary passage 211 may be incorporated in anelongated glass member 212 and redrawn to the desired size and thenassembled into larger units.

The structures illustrated in FIGS. 12A and 12B are similar to Figures11A and 118 except the conductive members are applied after theredrawing to desired size of plate 200 and 201" FIG. 12A) and plates200" and 201" (FIG. 128). In FIG. 12A, the conductors C are applied toexternal surfaces of plates 200" and 201" whereas in FIG. 128, theconductors C" are placed on the bottoms of grooves 203", respectively,and have a thin dielectric coating applied over same.

In Figure 13, center plate 220 has formed therein parallel grooves 221in one surface 222 and aligned grooves 223 in the opposite surface 224.Grooved plate 220 is sandwiched between viewing plate 226 and backingplate 227. Prior to redraw, grooves 223 are filled with indium or otherconductive alloy which is liquid at glass drawing temperature. Afterredraw of this structure, as in earlier structures, a transversetransparent conductor (not shown) can be applied to viewing plate 226,it can be baked out in a vacuum capillary gas passages 221 filled withgas and sealed to complete the device.

When large numbers of gas capillaries are formed during redrawoperation, the continuity of the bores may be determined by immersingone end of the tubes in a body of liquid, such as ink, to effect acapillary rise of liquids in all tubes having bore continuity. Moreover,such liquid can be used as an indicator of bore dimensions as well aswall thicknesses.

The tubes need not be redrawn as a unit or as a subunit of a largerpanel assembly. In fact, it may be preferred to process the capillarytubes individually. Thus, each tube in an assembly or array may beconsidered as a single elongated capillary gas chamber or continuum eachhandled on an individual basis prior to assembly in an array of tubesforming a panel. Individual rectangular capillary tubings are formed,checked for dimensional departures, dielectric strength and thendimensional departures, dielectric strength and parameters and thenselected capillaries tipped off or otherwise sealed at one end. Thesetubes may then be baked out in a vacuum and backfilled with the gaseousdischarge medium to any desired gas pressure. Such individual tubes maythen be flamed tipped or sealed with a hot wire, for example, to formindividual discharge capillaries or ampuls Each ampul or capillary maybe of any length desired and of any cross-sectional configuration suchas circular or rectangular. For example, a rectangular ampul orcapillary may have a thickness of 0.010 inch (10 mils), a width of 0.03.inch (30 mils) with a wall thickness of 0.001 (1 mil), and suchdimensions, because of the capillaries being formed from redrawn tubingwill be substantially inherently uniform throughout the length thereofso that the critical dielectric thickness and discharge gap parameterswill be uniform. Each such ampul or capillary may then be inspected ortested electrically and otherwise prior to assembly in a panel array asan intermediate step in the assembly of the panel. After testing theampuls or capillaries are arranged on a flat substrate having aconductor array transverse to the long dimension of the ampuls and thensecured thereon by adhesive or other securement means with the conductorarray being in intimate contact with the outside wall of the ampul. lfdesired, an array of individual ampuls may be sandwiched between a pairof plates having orthogonally related conductor pattern thereon or aconductor array may simply be printed or otherwise fonned on the ampulsor capillaries after assembly into panel arrays.

Although a number of embodiments have been disclosed herein, others willbe suggested by the disclosure and all such embodiments as fall withinthe spirit of the invention are intended to be covered by the claimshereof.

What is claimed is:

1. In a multiple discharge gas display/memory panel of the type in whichdiscrete discharges in a gas under pressure produces charges alternatelycollectable on surfaces of pairs of opposed dielectric members backed bypairs of conductors carrying operating alternating potentials,

a glass structure comprising a plurality of axially coplanar elongatedtubular glass capillary tube members formed as a monolayer andsimultaneously with each other, a gaseous discharge medium in saidtubes,

one of said conductors of said pairs being parallel to the bore of aglass tube member, respectively, and the other of said conductor beingdisposed at the opposite surface of the tubes and at a transverse angleto the first conductors, respectively.

2. The invention defined in claim 1 wherein said parallel tubularmembers of a set are tubes and wherein the width dimension of the boreof each tube is equal to the lateral width dimension of said conductors,respectively.

3. The invention defined in claim 1 wherein said parallel tubularmembers are rectangular in cross section and wherein each conductorlying parallel to the bore of a tubular member is greater in lateraldimension than the width of the bore of several of said tubes wherebythe bores of several of said tubes lie within the lateral dimension ofone of said conductors so that several discharges in the several tubes,respectively, are produced when operating potentials are applied toselected crossing conductors thereof.

4. The invention defined in claim 1 wherein said tubular members areessentially round tubes, the diameter of each bore of each tube issmaller than the width of the conductors paralleling same whereby thereare several discharges on application of operating alternatingpotentials to preselected conductors thereof.

5. The invention defined in claim 4 including solid glass fiber membersbetween adjacent tubular members.

6. The invention defined in claim 1 wherein said tubular members aresubstantially round tubes.

7. The invention defined in claim 6 including at least one solid glassfiber spacer member between each adjacent tubular member, respectively.

8. The invention defined in claim 7 wherein said solid fiber glassmembers are smaller in diameter than said tubular mem bers.

9. The invention defined in claim 7 wherein said solid glass fiberspacer members are circular in cross section and joined at their pointsof tangential contact with a hollow tubular member to form a groove forreceiving one of said conductor members, respectively.

10. The invention defined in claim 7 including at least one thin planarsupport substrate tangentially secured to said monolayer of capillarytubes and said glass fiber spacer members, respectively.

11. The invention defined in claim 10 wherein one of said conductors ison the opposite side of said plate from said tube.

1. In a multiple discharge gas display/memory panel of the type in whichdiscrete discharges in a gas under pressure produces charges alternatelycollectable on surfaces of pairs of opposed dielectric members backed bypairs of conductors carrying operating alternating potentials, a glassstructure comprising a plurality of axially coplanar elongated tubularglass capillary tube members formed as a monolayer and simultaneouslywith each other, a gaseous discharge medium in said tubes, one of saidconductors of said pairs being parallel to the bore of a glass tubemember, respectively, and the other of said conductor being disposed atthe opposite surface of the tubes and at a transverse angle to the firstconductors, respectively.
 2. The invention defined in claim 1 whereinsaid parallel tubular members of a set are tubes and wherein the widthdimension of the bore of each tube is equal to the lateral widthdimension of said conductors, respectively.
 3. The invention defined inclaim 1 wherein said parallel tubular members are rectangular in crosssection and wherein each conductor lying parallel to the bore of atubular member is greater in lateral dimension than the width of thebore of several of said tubes whereby the bores of several of said tubeslie within the lateral dimension of one of said conductors so thatseveral discharges in the several tubes, respectively, are produced whenoperating potentials are applied to selected crossing conductorsthereof.
 4. The invention defined in claim 1 wherein said tubularmembers are essentially round tubes, the diameter of each bore of eachtube is smaller than the width of the conductors paralleling samewhereby there are several discharges on application of operatingalternating potentials to preselected conductors thereof.
 5. Theinvention defined in claim 4 including solid glass fiber members betweenadjacent tubular members.
 6. The invention defined in claim 1 whereinsaid tubular members are substantially round tubes.
 7. The inventiondefined in claim 6 including at least one solid glass fiber spacermember between each adjacent tubular member, respectively.
 8. Theinvention defined in claim 7 wherein said solid fiber glass members aresmaller in diameter than said tubular members.
 9. The invention definedin claim 7 wherein said solid glass fiber spacer members are circular incross section and joined at their points of tangential contact with ahollow tubular member to form a groove for receiving one of saidconductor members, respectively.
 10. The invention defined in claim 7including at least one thin planar support substrate tangentiallysecured to said monolayer of capillary tubes and said glass fiber spacermembers, respectively.
 11. The invention defined in claim 10 wherein oneof said conductors is on the opposite side of said plate from said tube.